Not sure whether to post in mathematics or physics section. A circuit contains a cell of unit E.M.F. Use any combination of identical resistors in series and/or parrallel in order to create a voltage of x across a voltmeter connected anywhere on the circuit. Assume that there is no internal resistance or resistance in the wires, and the voltmeter does not draw any current. What is the easiest way to find the minimum number of resistors required for a given value of x (x<1 and x is rational, otherwise there is no solution)?